Zodiac Serial Murders:The Phantom Killer

“This is the Zodiac speaking”. With those words, written in a letter to The San Francisco Examiner, a killer was christened and a mystery born that continues to this day.

The letter, received by the newspaper on August 4 1969, was claiming credit for 2 sets of recent murders in the Bay Area around San Fransisco. It was the second letter from someone claiming to be the killer, but this time he gave himself his soon to be legendary name — ‘The Zodiac’.

More murders would follow, along with more letters to local newspapers and police. The Zodiac’s terrible crimes were been publically played out in the nation’s newspapers, with each twist and turn holding the American public under a grim spell.

And then he stopped. Less than a year after his first murder, the Zodiac killer simply stopped killing. The letters continued, filled with boasts and taunts, and other murders would occasionally be linked to the Zodiac but, officially at least, he seemed to have had his fill of killing.

At the time of the original police investigation, some detectives were skeptical the crimes were related, but mainly on account of the letters the general consensus was that a serial killer was at work around San Fransisco.

The Zodiac killer, as yet unnamed, wrote his first letter to Bay Area newspapers on July 31, 1969.

But despite the conviction they were after one man, the police departments of multiple jurisdictions were unable to develop a credible suspect. To date, the identity of the Zodiac killer remains a mystery, one that continues to provoke fierce speculation and debate in books, documentaries, and online forums.

A mind-boggling number of suspects have been suggested, and it has almost become a national pastime in America to claim the Zodiac was a deceased family member — fathers, brothers and uncles all suggested by relatives as the killer, often with accompanying books selling their theory.

Author Thomas Horan has built on the suspicions of some of the original investigators that the crimes were not connected to suggest the Zodiac killer never actually existed. If, as Horan surmises, the letters attributed to the killer were not genuine, then suddenly there is very little reason to believe the murders were even related.

Could the Zodiac killer himself, vividly conjured up in a series of letters to San Francisco Bay Area newspapers, really be an invention of an enterprising journalist keen to keep a sensational case on the front pages? Or the warped game of a hoaxer?

If so, the truth behind this most mysterious of unsolved crimes would be a mundane one. If properly examined, does the reality of Zodiac killer really dissolve into fiction? To find out, we must first summarize the purported facts of the case.

Chalk outline showing where David Faraday was murdered

According to the official story, the Zodiac’s murders began in late 1968 with the Christmastime murders of teenagers Betty Lou Jensen and David Faraday on December 20 at Lake Herman Road near Benicia, a small city in Solano county, California.

At approximately 11:00pm, an unknown assailant with a .22 semi-automatic pistol shot Faraday once in the head and Jensen 5 times in the back. Both died almost instantly and there were no signs of sexual molestation or robbery.

6 months later, at around midnight on July 4/5th 1969, a gunman shot 22 year old Darlene Ferrin and 19 year old Mike Mageau in a parking lot at Blue Rock Springs Park in Vallejo, 4 miles away from the Lake Herman Road attack.

Darlene Ferrin was murdered in the parking lot at Blue Rock Springs Park

Darlene Ferrin was shot 5 times and was pronounced dead on arrival at the hospital. Mageau survived, despite been shot 4 times in the face, neck and chest. Like the previous murders, there were no witnesses and no signs of robbery.

Around 40 minutes later, a man called the Vallejo police department to claim responsibility for the shooting, telling the police switchboard operator Nancy Slover than he shot the kids with a 9mm Luger. The caller also stated he killed “those kids last year”, a seeming reference to the Lake Herman Road murders.

On July 31st, someone claiming to be the killer sent 3 near-identical letters to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times declaring responsibility for both sets of murders.

Alongside the letters was a cryptogram, which when eventually broken revealed a rambling message that stated how its writer liked “KILLING PEOPLE BECAUSE IT IS SO MUCH FUN” and “TO KILL SOMETHING GIVES ME THE MOST THRILLING EXPERENCE”.

The first cipher was sent to 3 Bay Area newspapers on July 31 1969

A similar letter by the same writer was received by the San Francisco Examiner on August 4th, that offered more details the writer claimed proved he was the killer. In this letter, the writer christens himself ‘The Zodiac’.

On September 27 1969, Bryan Hartnell and Cecelia Shepard were tied up and stabbed multiple times by a man on the shore of Lake Berryessa near Napa, California. Shepard died 2 days later in hospital, but Hartnell survived and was able to give a description of his attacker.

According to Hartnell the man wore a strange costume — a black hood and bib, and claimed to be an escaped convict. Tieing the pair up, he stabbed them both repeatedly, then hiked a quarter of a mile to where the pair had parked their car and left a message on the door.

The message contained the dates of both this and the previous 2 attacks, and the murder weapon used in each. It was signed with the same circle-crosshair logo present on the letters. About 90 minutes later, someone phoned the Napa County Sherrif’s office to claim responsibility for the attack.

On October 11 1969, at around 10pm, cab driver Paul Stine was shot to death by his passenger in the Presidio Heights district of San Francisco. The killer took Stine’s wallet and keys, wiped down some of the blood from the cab, and fled as police arrived.

2 days later, a letter was received by the San Francisco Chronicle claiming responsibility for the murder. Alongside the letter, the writer included a piece of Paul Stine’s bloody shirt, offered as proof that he was really responsible.

Sketch based on surviving victim Brian Hartnell’s description of the killer

Primarily because of the letters, police believed these 5 murders were committed by the man calling himself the Zodiac. But despite a massive investigation across multiple police departments the case was never solved and the identity of the killer remains unknown to this day.

Dozens, if not hundreds of different theories have been put forward over the years as to the identity of the Zodiac killer, but to date nobody has ever been able to put together a particularly convincing case against anyone that withstands close scrutiny.

Of all these theories, the one that has gained most traction amongst the public originates with Robert Graysmith, a true crime writer who worked as a cartoonist at the San Franciso Chronicle during the Zodiac murders.

In Graysmiths 1986 book ‘Zodiac’, and its sequel ‘Zodiac Unmasked’ the author singles out Arthur Leigh Allen as the Zodiac. Allen was a convicted child molester who was briefly considered a suspect in 1969, but dismissed by the police because they were unable to find any evidence linking him to the murders.

Despite Graysmiths persistent accusations against Allen, repeatedly made in television interviews, he was almost certainly not the Zodiac. DNA tests on one of the letters did not match him, nor did a handprint found on another. Handwriting experts also could find no match between extensive examples of Allen’s handwriting and the Zodiac letters.

Since its publication, many experts on the case have thoroughly dismantled Graysmith’s book, exposing it as a mixture of myths, half-truths, and inventions concocted to present a non-existence case against an innocent man.

Robert Graysmith erroneously accused Arthur Leigh Allen of being the Zodiac killer.

Despite the falsity of Robert Graysmiths claims, it has not stopped them becoming the dominant modern narrative about the Zodiac case, used as the source for countless documentaries and other books. It was also the basis of a 2007 film about the case by director David Fincher.

With the failure of anyone to find any credible suspects in the case, could the theory that the Zodiac killer was some kind of hoax be right, and the murders attributed to him unrelated?

Evidence For

The many signs of the Zodiac

If not for the letters and phone calls attributed to the Zodiac killer, it is doubtful the 5 murders the killer claimed responsibility for would ever have been linked by the police.

Whilst the Lake Herman Road and Lake Berryessa attacks were committed against young couples, the Blue Rocks Springs victims were not a couple. Nor were they, as is often reported, in a ‘lovers lane’ area.

Darlene Ferrin and Mike Mageau were actually attacked in a busy parking lot close to a main road, with cars coming and going around them. This was a high-risk location for murder and a far cry from the remote beauty spots where the Zodiac made 2 of his purported attacks.

The third attack at Lake Berryessa is also quite different in style to the previous two sets of murders. Here, for the one and only time, the Zodiac wears a disguise — a black executioner’s hood with sunglasses over the eye-holes and a bib over his chest with the now familiar cross-circle symbol painted on it.

Whilst laying on the Zodiac imagery thick, he also spends a great deal of time talking with his victims, something he is not known to have done in any of the other murders. This is also the only known attack where he ties up his victims.

29-year-old Paul Stine was the Zodiac’s last victim, robbed and murdered whilst driving his cab in the middle of a San Fransico street, as bystanders looked on. This attack appears least like the others attributed to the Zodiac, and would have undoubtedly been dismissed as an all-to-common robbery gone wrong if not for the letter writer’s own claims to responsibility.

All of these seemingly disparate attacks used a different murder weapon. The first murders at Lake Herman Road were thought to have been committed with a .22 automatic pistol. The assailant of Paul Stine and at Blue Rock Springs used different 9mm semi-automatics, and the victims at Lake Berryessa were stabbed with a long knife.

There was no matching ballistics in any of the crimes attributed to the Zodiac, nor any other solid forensic evidence that linked them. Although fingerprints and palmprints were lifted at several of the crimes scenes, none of them ever matched each other.

To all intents and purposes, these appeared to be unrelated murders. Could it be that the Zodiac was not a genuine murderer, but a warped hoaxer claiming credit for unrelated crimes? Or separate criminals adopting the Zodiac’s widely publicised persona as a kind of alibi?

Clearly, if you commit a crime then blame it on an uncaught high-profile serial killer, a serial killer that could not possibly be you, then you have created a cast iron alibi for the crime you did commit.

The usual suspects

Although rarely mentioned in the numerous documentaries on the subject or Robert Graysmith’s books, there were strong alternative suspects in several of the individual crimes that were attributed to the Zodiac.

Solana Country Investigators at the time had good reason to believe the first attack at Lake Herman Road was drug related. 2 informants, in jail for a similar crime the year before, pointed to a drug-dealing associate of theirs named David Wally Ott as the shooter of Betty Lou Jensen and David Faraday.

Police had some corroboration of this ID from another witness and a confirmed account of a confrontation between Faraday and another drug dealer in which Faraday had threatened to turn him into the police.

Such drug and gang related violence was all-to-common in the San Franciso Bay Area in the late 60s — 10 people had been murdered in the previous year alone. If the Zodiac had not effectively ended the investigation by claiming credit for Jensen and Faraday’s deaths, other credible, albeit far less sensational suspects may well have been found.

Image thought to show Darlene Ferrin with her estranged ex-husband James Phillips Crabtree — was he her killer?

There was also a plethora of possible alternative suspects in the Blue Rock Springs attack on Ferrin and Mageau, including a rogue cop, the same drug gangs that may have been involved in the Lake Herman Road murders and Darlene Ferrin’s ex-husband James Phillips Crabtree.

If the murder of Ferrin had never been linked to the Zodiac, Crabtree, as her estranged ex-husband, would have been a prime suspect. The pair’s relationship was acrimonious and violent and even after Ferrin’s tragic death Crabtree would continue to talk about her in the most bitter and degrading terms. He was also arrested shortly after her death in the possession of a handgun similar to the one used in the murder.

Despite the fact it would have been routine for Crabtree to have been considered a prime suspect, amazingly it wasn’t until months later that the police briefly looked into him in connection with Ferrin’s murder, such was the power that the idea of a ‘Zodiac killer’ had on the police investigation.

If Crabtree was Ferrin’s murderer, what about the letters? 2 factors tentatively suggest the possibility he may have written at least some of the earlier ones.

As a trained cryptographer, Crabtree had the credentials to have written the ciphers contained in the Zodiac’s first letters. He also uses the Zodiacs trademark circle-crosshairs symbol in a postcard he wrote to an occult bookshop in England sometime in 1969. It’s not clear whether this was posted before or after the symbol appears in the letters, but either way it’s striking.

Whilst there is little to suggest Crabtree was responsible for any of the other murders, could he have written the letters and added Jensen and Faraday as fictional Zodiac victims to act as a kind of alibi for himself in the murder or Darlene Ferrin?

It has long been speculated that the third attack at Lake Berryessa may have been a copycat, a twisted and disturbed person taking on the persona of the Zodiac as reported so vividly in the media during the previous weeks.

Whilst the killer at Lake Berryessa uses the Zodiac’s ‘logo’, and writes a Zodiac like a message on the car door, everything else about the attack only bears a superficial resemblance to the Zodiac’s previous alleged murders.

This is also the only attack the writer of the letters never mentions, somewhat odd considering his primary motive always appeared to be to take public credit for his work. The change of killing method also singles out Lake Berryessa as unusual.

The killer at Lake Berryessa left a message on the victim’s car door

Whilst by no means unprecedented for a serial killer to change murder technique, moving from shooting to stabbing is quite rare. Shooting is an impersonal and clinical method of killing, giving the gunman a degree of control and distance from his crime.

Stabbing, however, is up-close, messy and personal, the murderer gets his victims blood on his hands. The contrast between the two methods reveals a very different pathology in the killer and quite possibly a different killer altogether.

There are other problems in the Lake Berryessa attack. Although the Zodiac left a message on the car door of his victims, no trace of blood is present on the door, despite the fact he had conducted a frenzied knife attack, stabbing Hartnell and Shepard a total of 16 times, just moments before. How had the killer manages to so thoroughly clean his hands?

The handwriting on the car door also shows some distinct differences between the writing evident in the Zodiac letters, although these could be accounted for by the unusual angle he may have had to adopt to write on the door. Either way, it cannot reliably be tied to the ‘real’ Zodiac in either form or content with any certainty.

The last murder attributed to the Zodiac killer was cab driver Paul Stine. Like many of the previous attacks, this would no doubt have been treated by the police as a routine, entirely unrelated crime if it were not for the Zodiac’s claims of responsibility.

Stine had been shot and robbed of his wallet, reminiscent of a spate of other cab robberies that had plagued the area around that time. Eyewitnesses who saw the killer leave the cab described the assailant as a white man with a crew cut and glasses aged between 25–30.

This was one of only 2 descriptions we can reliably assume were of the killer. But the other, from surviving Zodiac victim Mike Mageau, describes a shooter who did not wear glasses and had short curly hair, not a crew cut.

Police sketch of Paul Stine’s killer

Stines killer, whoever it was, certainly appeared to be someone other than the person who wrote the letters. In an anniversary special on the Zodiac killings published in 1991, the Napa times reported that a bloody fingerprint from the Stine cab did not match latent prints lifted off the letters.

Again, none of the forensic evidence gathered from the Stine murder scene, the prints or the ballistics, provided any link at all to any of the other crimes attributed to the Zodiac.

Only the claims of responsibility in a series of letters, sent to local newspapers by someone calling themselves the Zodiac, and a couple of phone calls to the police, provided any links between the crimes. But just how believable are these?

This is the Zodiac speaking

The first problem with the Zodiac letters starts right at the beginning, with the 2 murders at Lake Herman Road in late 1968. For a killer so keen to take credit for and boast about his actions, it takes him more than 6 months to make any mention of these murders.

His first brief reference is in a phone call made to the police shortly after the second attack on Darlene Ferrin and Mike Mageau, in which he states — “I want to report a murder. If you will go one mile east on Columbus Parkway you will find kids in a brown car. They were shot with a nine millimeter Luger. I also killed those kids last year. Goodbye”.

Someone phoned the police from this Vallejo phone booth claiming responsibility for the murders

Whilst he offers nothing that can corroborate his claim to be responsible for the December murders, he does provide one checkable fact for the July 4 attack — that he used a 9mm Luger.

For anyone who had discussed the matter with detectives, overheard police transmissions or been around the murder scene, it was a reasonable assumption that Ferrin was killed with a Luger because of the bullets and shells found by police.

But subsequent analysis by ballistics experts found that the murder weapon was not a Luger, but a similar semi-automatic pistol that took the same ammunition — a Browning Hi-Power. On the night of the call, this fact was known only to the true killer, and the caller appeared unaware of it.

Clearly the phone call itself provided no compelling evidence that the caller was responsible for the December and July 4 murders, and actually tended to argue against the idea.

I want to report a murder. If you will go one mile east on Columbus Parkway you will find kids in a brown car. They were shot with a nine millimeter Luger. I also killed those kids last year. Goodbye

In the first letter sent to Bay Area newspapers on July 31, the writer provides evidence that he says proves he was responsible for the Lake Herman Road and Darlene Ferrin murders. Vallejo Police Chief Jack Stiltz was, however, unconvinced

Talking to reporters, Stiltz said that the writer had demonstrated no knowledge that could not have been gleaned from the newspapers or by overhearing police chatter. Hoax letters, phone calls and even false confessions are a depressingly familiar prospect for any major police department caught in the middle of a high-profile case and Stiltz’ scepticism was warranted.

A few days later, the writer tries again. In his second letter, mailed to the Examiner, he tells a fanciful tale about taping a torch to his gun in the December murders, but offers no other details that might prove he was the real killer, such as what clothes his victims were wearing, something not reported in the newspapers.

A second letter received tried to offer proof that the writer was the real killer

He offers more information about the murder of Darlene Ferrin, claiming that he shot Mike Mageau in the knee and did not, as reported in the papers, leave the scene at high speed with tires squealing, instead leaving slowly so as not to draw attention to himself.

Both these ‘facts’ offered by the writer, now calling himself The Zodiac, appear to be wrong. Mike Mageau was not shot in the knee, and both he and other witnesses did describe the shooter as leaving the scene at high speed, with engines racing and tires squealing.

The writer of these first 2 letters do appear to be the same person, but nothing contained in them genuinely provided any unarguable evidence that he was the true perpetrator of the 2 attacks, or even anything that could not have been learnt from other sources.

The next canonical Zodiac attack came at Lake Berryessa in September. Curiously, the assailant there had become somewhat shy, not only hiding behind his bizarre ‘Zodiac’ disguise but failing to write any letters boasting about his actions.

He does, however, leave a message on the victims’ car door, consisting of the dates of the previous attacks and the latest one, signed with the Zodiac’s crosshair logo. Shortly later, someone phoned the Napa police claiming credit for the ‘double murder’, but offered no information only known to the killer.

Likewise, the car door message contains nothing about the previous attacks not already in the public domain, and only bears a superficial resemblance to the handwriting from the letters. Tellingly, the writer does not seem to know his own name ‘Zodiac’. This would be understandable if the writer was a hoaxer since that fact had not yet been publicly revealed by the police.

Everything about the Lake Berryessa murders suggests a copycat attack by someone other than the writer of the letters, and the car door message and phone call provide no evidence to suggest otherwise.

When the letter from the Zodiac appeared on October 13 claiming credit for the murder of cab driver Paul Stine, the police were surprised as they had believed the killing was simply a robbery-murder, just like the spate of similar crimes against cab drivers that had plagued the city all year.

The text of the Zodiac’s October 13 letter makes several dubious claims and contain no insights that would prove he was the true killer of Stine. San Francisco Police Inspector Martin Lee was unimpressed by the Zodiac’s latest correspondence.

“His boast of being in the area we were searching while we were searching it is a lie”, Lee said in a San Francisco Chronicle report on the case. The article further stated that detectives were well aware that many of the Zodiac’s previous claims were also lies.

The letter writer sent a piece of Paul Stine’s bloody shirt to the San Fransisco Chronicle

This latest letter could easily be dismissed as another hoax if not for a piece of bloody cloth, seemingly ripped by the killer from Paul Stine’s shirt, sent alongside the letter to the Chronicle. Of all of the evidence offered by the writer of the letters, this was by far the most convincing.

Whilst the piece of shirt did nothing to prove the Zodiac was responsible for the earlier murders, it certainly seems compelling evidence he must have killed Stine. But could the writer have acquired the bloody shirt some other way?

The possibility that someone, a cop, a reporter or someone else with insider connections had somehow managed to obtain the shirt piece after the murder cannot be overlooked. It would not be the first time that police investigations had been breached like this.

The history of crime detection is replete with hoaxers and frauds that have managed to garner what looked like insider information ‘only the killer could have known’.

Only the killer could have known

There are numerous examples of murder investigations been derailed by hoaxers who seem to have information that convinces the police they must be the real killer.

The granddaddy of all serial killer cases — Jack the Ripper, contains several parallels with the Zodiac case. Like the Zodiac, Jack gave himself his famous name in a taunting letter he wrote to the police. Several other letters were written by someone claiming to be Jack, a serial murderer of prostitutes in Whitechapel, London in 1888.

All of the letter’s attributed to Jack the Ripper are thought to be hoaxes

Some of these letters contain details that appeared to show the writer knew details of the crime scenes not generally known. Another was even accompanied, like the Stine shirt, by a piece of physical evidence — a human kidney said to have come from the Ripper’s 4th victim Catherine Eddowes.

Today, the majority of Ripper historians believe all of the letters attributed to ‘Jack the Ripper’ are hoaxes. Indeed whilst the murders were very real, the character of Jack the Ripper evoked in the letters was a fictional creation, probably dreamt up by journalist Thomas Bulling in order to keep the lurid case on the front pages.

It’s quite possible Bulling was able to insert authentic sounding facts into some of the letters by his associations with rogue police detectives, the incestuous two-way sharing of information between the press and the police as prevalent then as it is in today’s tabloid world.

Could the Zodiac letters be the creation of an enterprising 1960s equivalent of Thomas Bulling? Could the authentic details in the letters have been given to him by his contacts in the police department?

Other examples indicate insider contacts in the police are not necessary for a hoaxer to create a convincing facsimile of a real killer. In the late 1970s in Northern England, police were closing in on serial killer Peter Sutcliffe when a hoaxer managed to deflect the investigation down a cul-de-sac which probably cost at least 3 women their lives.

Dubbed ‘Wearside Jack’, John Samuel Humble sent letters and an audio tape to the Yorkshire Police that convinced them he had knowledge only the real killer could have known. Because of this, and Humble’s strong Wearside accent, the whole investigation was moved away from West Yorkshire, were Sutcliffe operated, to the North East of England.

In actual fact, Humble had no inside information, he just read the papers and paid attention. Because of the size and complexity of the inquiry, police had simply become unaware of what information had and had not become public. Humble was finally caught 24 years later and sentenced to 8 years for perverting the course of justice.

Albert De Salvo seemed to know details of crimes he probably didn’t commit

A contemporary serial killer case to the Zodiac is that of Albert de Salvo — the Boston Strangler. De Salvo confessed to all 13 murders attributed to the Strangler and was sentenced to life imprisonment in 1967, just a year before the Zodiac murders began.

Despite the conviction, there is a growing belief amongst forensic investigators that De Salvo was innocent of at least some of the murders, and as a compulsive liar was able to insert convincing sounding, but erroneous information into his confessions to fool the police.

Crime author Casey Sherman believes some of the younger victims may have been unrelated murders disguised by the perpetrators to look like Strangler murders to provide them with an alibi, a suspicion echoed in the Zodiac case.

Evidence against

The bigger picture

Despite the vast number of differing theories as to the identity of the Zodiac killer, most of them agree on one thing — that a single individual committed the murders, made the phone calls, and wrote the letters attributed to the Zodiac.

A certain baseline of generally uncontested assumptions exists that are accepted by most theorists and even the original investigators in the case. If they are true, then it makes the idea that the Zodiac killer was a hoax or never really existed hard to countenance.

Law enforcement at the time, and most theorists today, believe that the writer of the letters and the individual who wrote the message on the car door of the victims at Lake Berryessa were the same person, due to handwriting matches made by experts like Sherwood Morrill.

If the letter writer really was a hoaxer, rather than a murderer, then he would have had to have somehow stumbled upon the Lake Berryessa crime scene by chance in order to be present to write on the car door, which seems unlikely.

The pieces of bloody shirt the letter writer sent appeared to prove he was the true killer of Paul Stine

Furthermore, unless he had inside help from the police, the letter writer almost certainly murdered cab driver Paul Stine, because of the piece of Stine’s bloodied shirt he sent alongside his letter taking responsibility for the crime.

It seems likely then, that the letter writer calling himself the Zodiac, probably did murder Cecelia Shepard at Lake Berryessa and Paul Stine in San Fransisco. But did he commit the other Zodiac murders or just claim credit for them?

If the other canonical Zodiac murders were not the work of the same man, then we must posit multiple killers committing similar murders in a relative small area at the same time, which seems statistically improbable.

The Zodiac’s signature

Although the killings do appear to show different methodologies, this is not as unusual as is often thought. In criminologist Robert D Keppel’s book about serial murderers — Signature Killer, he describes what he calls ‘m.o. purism’, a tendency amongst law enforcement to only link separate murders if the method used is exactly the same.

According to Keppler, serial killers do sometimes change their m.o. — modus operandi, as they strive to become more comfortable in the specific circumstances of each successive murder. But what doesn’t change, according to former FBI criminal profiler John Douglas, is the killers ‘signature’.

“We came to realize that while m.o. was important, in certain types of crimes it wasn’t nearly as important as what I call ‘signature’”, Douglas wrote. “The unique aspect that was critical not so much to accomplish the crime as to satisfy the perpetrator emotionally”.

For the Zodiac, the signature of his murders seemed to be the exerting of control and the demonstration of his superiority over the public and the police via his letters, a common thread that does seem to link the crimes, even where the methodologies are different.

It could also be argued that the different methods the Zodiac employed in his crimes were simply employed out of expediency. For example, his use of a disguise and knife at Lake Berryessa may be because he committed the attack in daylight and wished to avoid detection.

But whilst that attack and the Paul Stine murder appeared to be very different, both exhibited the same ‘signature’ use of messages and phone calls to the police that sought to assert the Zodiac’s control over the investigation.

The Zodiac killer’s threat to blow up a school bus caused panic in San Fransisco

This need for control culminated in the threat he made in his October 13 1969 letter to the Chronicle in which he said he would blow up a school bus and pick off the children as they fled. This essentially singled him out as a kind of terrorist, using his crimes and the letters to cause fear and anxiety amongst the populace.

The Zodiac murders have almost become a parlour game, a giant jigsaw puzzle with many of the pieces missing. Like many such cases where hard facts are few and far between, speculation and assumption have filled the gaps.

Often, like the half truths and gossip packaged as investigative journalism by Robert Graysmith, facts get substituted by fiction in the public’s mind.

But even though much of Graysmith’s mythology has been exposed as nonsense, many of his basic assumptions about the case are still widely accepted as correct by most theorists and investigators.

By challenging these most fundamental assumptions about the case, authors like Thomas Horan have created a credible argument that questions the very existence of the Zodiac killer.

When the speculation and myths are stripped away, what’s left does suggest the possibility that the famous Zodiac killer may be a phantom, a fictional bogeyman we choose to keep alive because sometimes our darkest fears make for a far better story than the mundane truth.